Unit 5 (chapter 10)- DNA, protein synth, genetic engineering Flashcards
~18 questions
DNA
Stores gen. instructions
-deoxyribonucleic acid
-double stranded
-thymine no uracil
-stays INSIDE nucleus
RNA
ribonucleic acid
single-stranded
uracil no thymine
goes OUTSIDE nucleus
Nucleotide base-pairs
A - T/U
C - G
m (messenger) RNA
RNA that travels to ribosome and has codons that correspond to tRNA anticodon
t (transfer) RNA
carries aa’ s and anticodons that when bonded to mRNA codons, releases aa’s to form pp chains
r (ribosomal) RNA
makes up ribosomal subunits
genes
portions of DNA that code for specific traits
what do you use to read a codon chart?
MRNA ONLY MRNA!!!!!!!!!!!!!!!!!!!!
codon chart
chart that uses MRNA to translate gen. code to corresponding aa’ s
transcription- initiation
- initiation- promoter starts sequence when RNA polymerase attaches
transcription- elongation
- elongation- RNA grows longer as RNA polymerase adds comp. bases and starts to pull away from DNA template
transcription- termination
- termination- RNA polymerase reaches terminator and detaches, DNA strands rejoin
RNA polymerase
adds/binds comp. bases from DNA template to form RNA
what is translation?
mRNA —> tRNA —> aa
what is transcription-?
DNA —> mRNA
translation- initiation
mRNA goes to ribosome and subunits bind together
translation- elongation
aa’s are released from tRNA as their anticodons bind to mRNA codons and added to pp chain
translation- termination
stop codon tells translation to stop elongating; pp is freed and ribosome splits
protein synthesis
pp chains fold together to create protein
what are some things that can cause a protein to stop functioning/denature?
pH changes
temp changes
how many possible codons are there?
how many aa’s are there?
64
20
DNA polymerase
make DNA strands by assembling nucleotides and “proof-reads” when assembling too
helicase
unzips DNA strands by breaking H bonds holding the bases together
primase
makes primer so DNA polym. knows where to start replicating
ligase
glues DNA fragments (okazaki) together
nucelotides
monomer of nucleic acids
what are nucleotides (DNA, RNA) made of?
sugar, phosphate, nitrogenous bases (A, G, C, T, U)
purine
double rings; guanine and adenine
pyrmidines
single rings; thymine, cytosine, uracil
DNA replication steps
- starts at origin
- helicase unzips strands
- primase makes primers at both ends
- DNA polym. builds new strands
- ligase glues okazaki fragments
when does DNA replication need to happen?
interphase, before a cell splits
enzymes (-ase)
proteins that speed up/ catalyze reactions
what type of bonds pair nucleotide bases?
hydrogen bonds- weaker
why is the bottom strand in DNA replication called the lagging strand?
since DNA polymerase can only build in the 5’ to 3’ direction, it needs to keep going up (keep adding primers) to where the unwinding is happening
okazaki fragments
fragments made due to lagging strand; sealed together by ligase
what is the end product of DNA replication?
two identical double stranded DNA molecules
semi- conservative one strand new, one strand old
mutations
change in a DNA sequence
insertion, deletion, substitutions
base insertions or deletions
(frame shift mutations)
adding or subtracting bases
(usually disastrous consequences)
base substitutions
replacement of one base for another
-can have no effect
- if 3rd base is changed, likely no change will happen
start codon
methionine (MET)
stop codon
3 of these; code for no AA
upside to mutations
diversity
introns
“intruders” - junk/noncoding DNA that is removed during splicing
exons
“excellent” -coding regions od DNA; they are spliced together
small ribosomal subunit
binding sites for mRNA
large ribosomal subunit
binding sites for tRNA
does splicing need to happen in prokaryotes?
no! mRNA is prepared already
cap and tail
protect RNA from enzymes and help ribosomes recognize it as mRNA
what type of RNA is spliced?
mRNA
RNA splicing
introns are removed and exons spliced together in nucleus then go to ER (Endoplasmic reticulum)
RNA editing (very rare)
insertion, deletion, substitution of a base when errors occur in transcription
sugar-phosphate backbone
supports the anti-parallel structure of nucleic acids
- 3’ to 5’ and 5’ to 3’
how did Franklin discover the structure of DNA?`
x-ray diffraction
